In this study, we developed a metal–semiconductor field-effect transistor (MESFET) using a Ge-doped α-Ga2O3 channel layer grown via mist chemical vapor deposition (CVD). As a buffer layer, Fe-doped α-Ga2O3 was deposited between the Ge-doped α-Ga2O3 channel layer and the m-plane sapphire substrate to reduce the influence of threading dislocations and suppress current leakage. Furthermore, an n+ contact layer heavily doped with Ge was deposited on the channel layer to reduce the contact resistance. The carrier concentration and Hall mobility of the channel layer were 2.1 × 1017 cm−3 and 44 cm2 V−1 s−1, respectively. The transfer length method indicates that the contact between the metal and the n+ layer exhibits Ohmic behavior with a resistance as low as 16 Ω mm. The MESFET exhibited a maximum current of 24 mA/mm and an on-resistance of 587 Ω mm at VGS = 2 V. The Ion/Ioff ratio exceeded 109. The breakdown voltage was 364 V, the leakage current between the drain and the source was below 10−5 mA/mm, and the power figure of merit was 1.2 MW/cm2. These results demonstrate that the mist CVD-derived Ge-doped α-Ga2O3 can give rise to a MESFET with good performance.
在这项研究中，我们开发了一种金属半导体场效应晶体管（MESFET），它使用了通过雾状化学气相沉积（CVD）生长的掺杂 Ge 的 α-Ga2O3 沟道层。作为缓冲层，在掺杂 Ge 的 α-Ga2O3 沟道层和 m 面蓝宝石衬底之间沉积了掺杂 Fe 的 α-Ga2O3，以减少穿线位错的影响并抑制电流泄漏。此外，还在沟道层上沉积了大量掺杂 Ge 的 n+ 接触层，以降低接触电阻。沟道层的载流子浓度和霍尔迁移率分别为 2.1 × 1017 cm-3 和 44 cm2 V-1 s-1。转移长度法表明，金属和 n+ 层之间的接触呈现欧姆行为，电阻低至 16 Ω mm。在 VGS = 2 V 时，MESFET 的最大电流为 24 mA/mm，导通电阻为 587 Ω mm。离子/关断比超过 109。击穿电压为 364 V，漏极与源极之间的漏电流低于 10-5 mA/mm，功率值为 1.2 MW/cm2。这些结果表明，雾状 CVD 衍生的掺杂 Ge 的 α-Ga2O3 能够产生性能良好的 MESFET。
{"title":"24-mA/mm metal–semiconductor field-effect transistor based on Ge-doped α-Ga2O3 grown by mist chemical vapor deposition","authors":"Takeru Wakamatsu, Yuki Isobe, Hitoshi Takane, Kentaro Kaneko, Katsuhisa Tanaka","doi":"10.1063/5.0231630","DOIUrl":"https://doi.org/10.1063/5.0231630","url":null,"abstract":"In this study, we developed a metal–semiconductor field-effect transistor (MESFET) using a Ge-doped α-Ga2O3 channel layer grown via mist chemical vapor deposition (CVD). As a buffer layer, Fe-doped α-Ga2O3 was deposited between the Ge-doped α-Ga2O3 channel layer and the m-plane sapphire substrate to reduce the influence of threading dislocations and suppress current leakage. Furthermore, an n+ contact layer heavily doped with Ge was deposited on the channel layer to reduce the contact resistance. The carrier concentration and Hall mobility of the channel layer were 2.1 × 1017 cm−3 and 44 cm2 V−1 s−1, respectively. The transfer length method indicates that the contact between the metal and the n+ layer exhibits Ohmic behavior with a resistance as low as 16 Ω mm. The MESFET exhibited a maximum current of 24 mA/mm and an on-resistance of 587 Ω mm at VGS = 2 V. The Ion/Ioff ratio exceeded 109. The breakdown voltage was 364 V, the leakage current between the drain and the source was below 10−5 mA/mm, and the power figure of merit was 1.2 MW/cm2. These results demonstrate that the mist CVD-derived Ge-doped α-Ga2O3 can give rise to a MESFET with good performance.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"2 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tiancheng Zhao, Yuan Xu, Jiacheng Liu, Xiang Bao, Liu Yuan, Deen Gu
Temperature serves as a pivotal factor influencing information transmission and computational capacity in neurons, significantly affecting the function and efficiency of neural networks. However, the temperature dependence of VO2-based artificial neuron, which is one of the highly promising artificial neurons, has been hardly reported to date. Here, high-performance VO2 devices with NDR features are prepared by rapid annealing and electroforming processes. We constructed VO2-based artificial neurons with output properties similar to those of biological neurons on the basis of the Pearson–Anson oscillation circuit. The temperature-dependent behavior of VO2 neurons was fully investigated. Increasing temperature leads to a decrease in the peak-to-peak value of the output spikes of VO2 neurons. The spike period of VO2 neurons remains relatively stable near room temperature, but it decreases as the temperature reaches above 26 °C. These temperature-dependent features of VO2 neurons are similar to the ones of biological neurons, suggesting a natural advantage of VO2-based artificial neurons in mimicking biological neural activity. These findings contribute toward comprehending and regulating the temperature-dependent behavior of artificial neurons based on Mott memristor.
{"title":"Temperature-dependent behavior of VO2-based artificial neurons","authors":"Tiancheng Zhao, Yuan Xu, Jiacheng Liu, Xiang Bao, Liu Yuan, Deen Gu","doi":"10.1063/5.0231840","DOIUrl":"https://doi.org/10.1063/5.0231840","url":null,"abstract":"Temperature serves as a pivotal factor influencing information transmission and computational capacity in neurons, significantly affecting the function and efficiency of neural networks. However, the temperature dependence of VO2-based artificial neuron, which is one of the highly promising artificial neurons, has been hardly reported to date. Here, high-performance VO2 devices with NDR features are prepared by rapid annealing and electroforming processes. We constructed VO2-based artificial neurons with output properties similar to those of biological neurons on the basis of the Pearson–Anson oscillation circuit. The temperature-dependent behavior of VO2 neurons was fully investigated. Increasing temperature leads to a decrease in the peak-to-peak value of the output spikes of VO2 neurons. The spike period of VO2 neurons remains relatively stable near room temperature, but it decreases as the temperature reaches above 26 °C. These temperature-dependent features of VO2 neurons are similar to the ones of biological neurons, suggesting a natural advantage of VO2-based artificial neurons in mimicking biological neural activity. These findings contribute toward comprehending and regulating the temperature-dependent behavior of artificial neurons based on Mott memristor.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"34 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Functional gradient materials (FGMs) possess gradient-varying properties, which make them important in applications for connecting different materials and inhomogeneous environments. Ferroelectric single crystals have multiple excellent physical properties, but it is difficult to design gradient properties during the crystal growth. Here, a method is reported to achieve gradient piezoelectric properties in the tetragonal Mn&Fe-doped KTa1−xNbxO3 (Mn&Fe: KTN) crystals by alternating current poling and internal strain design. Furthermore, opposite piezoelectric coefficients are obtained in the direction perpendicular to the applied electric field, with a gradient variation from −221 to 227 pC/N. This phenomenon has been revealed to result from the co-regulating effect of flexoelectric field and alternating current electric field on defect dipoles and domain structures. This study contributes to the fabrication of functional gradient piezoelectric single crystals and expands the application scenarios of FGMs.
{"title":"Controllable gradient piezoelectric properties in ferroelectric single crystals","authors":"Xinyu Jin, Ming Qiu, Xiangda Meng, Yu Wang, Bohan Xing, Xing Wen, Jinyu Ruan, Xiaolin Huang, Xiaoou Wang, Chengpeng Hu, Peng Tan, Hao Tian","doi":"10.1063/5.0242972","DOIUrl":"https://doi.org/10.1063/5.0242972","url":null,"abstract":"Functional gradient materials (FGMs) possess gradient-varying properties, which make them important in applications for connecting different materials and inhomogeneous environments. Ferroelectric single crystals have multiple excellent physical properties, but it is difficult to design gradient properties during the crystal growth. Here, a method is reported to achieve gradient piezoelectric properties in the tetragonal Mn&Fe-doped KTa1−xNbxO3 (Mn&Fe: KTN) crystals by alternating current poling and internal strain design. Furthermore, opposite piezoelectric coefficients are obtained in the direction perpendicular to the applied electric field, with a gradient variation from −221 to 227 pC/N. This phenomenon has been revealed to result from the co-regulating effect of flexoelectric field and alternating current electric field on defect dipoles and domain structures. This study contributes to the fabrication of functional gradient piezoelectric single crystals and expands the application scenarios of FGMs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"188 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna Wirth-Singh, Arturo Martin Jimenez, Minho Choi, Johannes E. Fröch, Rose Johnson, Tina Le Teichmann, Zachary Coppens, Arka Majumdar
Lenses with dynamic focal length, also called zoom functionality, enable a variety of applications related to imaging and sensing. The traditional approach of stacking refractive lenses to achieve this functionality results in an expensive, heavy optical system. Especially for applications in the mid-infrared, light weight and compact form factor are required. In this work, we use a meta-optic triplet to demonstrate zoom imaging at mid-wave infrared wavelengths. By varying the axial distances between the optics, the meta-optic triplet achieves high-quality imaging over a zoom range of 5×, with a 50° full field of view in the widest configuration and an aperture of 8 mm. This triplet system demonstrates the potential for meta-optics to reduce conventional components in complex and multi-functional imaging systems to dramatically thinner and lighter components.
{"title":"Meta-optics triplet for zoom imaging at mid-wave infrared","authors":"Anna Wirth-Singh, Arturo Martin Jimenez, Minho Choi, Johannes E. Fröch, Rose Johnson, Tina Le Teichmann, Zachary Coppens, Arka Majumdar","doi":"10.1063/5.0227368","DOIUrl":"https://doi.org/10.1063/5.0227368","url":null,"abstract":"Lenses with dynamic focal length, also called zoom functionality, enable a variety of applications related to imaging and sensing. The traditional approach of stacking refractive lenses to achieve this functionality results in an expensive, heavy optical system. Especially for applications in the mid-infrared, light weight and compact form factor are required. In this work, we use a meta-optic triplet to demonstrate zoom imaging at mid-wave infrared wavelengths. By varying the axial distances between the optics, the meta-optic triplet achieves high-quality imaging over a zoom range of 5×, with a 50° full field of view in the widest configuration and an aperture of 8 mm. This triplet system demonstrates the potential for meta-optics to reduce conventional components in complex and multi-functional imaging systems to dramatically thinner and lighter components.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"35 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Robert A. Makin, Andrew S. Messecar, Steven M. Durbin
While it is widely appreciated that disorder is intricately related to observed sample-to-sample variation in property values, outside of very specialized cases, analysis is often qualitative in nature. One well-understood quantitative approach is based on the 1930s work of Bragg and Williams, who established an order parameter S, which ranges from unity in the case of a perfectly ordered structure to zero in the case of a completely randomized lattice. Here, we demonstrate that this order parameter is directly related to charge carrier mobility in undoped GaN. Extrapolating experimental points yields a value of 1640 cm2/Vs for the maximum room temperature mobility in stoichiometric material, with higher values potentially accessible for Ga-rich material. Additionally, we present a model for observed trends in carrier concentration based on the occurrence of distinct structural motifs, which underpin S. The result is an alternative perspective for the interplay between lattice structure and charge carriers that enables a predictive model for tuning mobility and carrier concentration in undoped material.
虽然人们普遍认为无序与所观察到的样本间属性值的变化密切相关，但除了非常特殊的情况外，分析通常都是定性的。一种广为人知的定量分析方法是基于布拉格和威廉姆斯在 20 世纪 30 年代的研究成果，他们建立了一个有序参数 S，其范围从完全有序结构的统一到完全无序晶格的零。在这里，我们证明了这个有序参数与未掺杂氮化镓中的电荷载流子迁移率直接相关。对实验点进行外推，可得出化学计量材料的最大室温迁移率值为 1640 cm2/Vs，而富含镓的材料可能会达到更高的值。此外，我们还提出了一个基于不同结构图案的载流子浓度观测趋势模型，该结构图案是 S 的基础。结果从另一个角度说明了晶格结构与电荷载流子之间的相互作用，从而为调整未掺杂材料中的迁移率和载流子浓度提供了一个预测模型。
{"title":"Disorder and its impact on mobility of undoped GaN","authors":"Robert A. Makin, Andrew S. Messecar, Steven M. Durbin","doi":"10.1063/5.0244197","DOIUrl":"https://doi.org/10.1063/5.0244197","url":null,"abstract":"While it is widely appreciated that disorder is intricately related to observed sample-to-sample variation in property values, outside of very specialized cases, analysis is often qualitative in nature. One well-understood quantitative approach is based on the 1930s work of Bragg and Williams, who established an order parameter S, which ranges from unity in the case of a perfectly ordered structure to zero in the case of a completely randomized lattice. Here, we demonstrate that this order parameter is directly related to charge carrier mobility in undoped GaN. Extrapolating experimental points yields a value of 1640 cm2/Vs for the maximum room temperature mobility in stoichiometric material, with higher values potentially accessible for Ga-rich material. Additionally, we present a model for observed trends in carrier concentration based on the occurrence of distinct structural motifs, which underpin S. The result is an alternative perspective for the interplay between lattice structure and charge carriers that enables a predictive model for tuning mobility and carrier concentration in undoped material.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"4 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we study the acoustic forces acting on particles due to sound scattering at the interface with an elastic substrate. Utilizing the Green's function formalism, we predict that excitation of a leaking Rayleigh wave results in a strong modification of the acoustic pressure force acting on a monopole scatterer and changes the equilibrium position of particles above the substrate surface. We also showed that the presence of a substrate changes the configuration of the acoustical binding of two particles due to multiple rescattering of acoustic waves from the interface. The reported results propose the method of acoustic manipulation via surface wave excitation and demonstrate the effect of elastic media in acoustical trapping of micro-objects.
{"title":"Acoustic forces near elastic substrate","authors":"V. Kleshchenko, K. Albitskaya, M. Petrov","doi":"10.1063/5.0233891","DOIUrl":"https://doi.org/10.1063/5.0233891","url":null,"abstract":"In this work, we study the acoustic forces acting on particles due to sound scattering at the interface with an elastic substrate. Utilizing the Green's function formalism, we predict that excitation of a leaking Rayleigh wave results in a strong modification of the acoustic pressure force acting on a monopole scatterer and changes the equilibrium position of particles above the substrate surface. We also showed that the presence of a substrate changes the configuration of the acoustical binding of two particles due to multiple rescattering of acoustic waves from the interface. The reported results propose the method of acoustic manipulation via surface wave excitation and demonstrate the effect of elastic media in acoustical trapping of micro-objects.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"18 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Determining the effective electrical properties of a multiphase medium is essential for understanding its performance. However, accurately characterizing the internal structure and calculating the effective electrical properties of complex multiphase media can be challenging, often resulting in divergent results from different models. In this study, we propose a connectivity dependent model for mixed media based on the effective medium approximation, which incorporates structural influences. This model simplifies itself to analytical forms in specific scenarios, such as simple series and parallel configurations. Our model demonstrates two key advantages: First, the model parameters depend solely on the shape distribution of each phase within the medium, making it applicable to multiphase systems (≥3) without requiring additional corrections. Second, it can predict the percolation threshold and provide insights into permeability and connectivity analyses of the medium. We demonstrate the effectiveness and versatility of our model through a series of parameter analyses and comparisons with experimental data.
{"title":"A connectivity dependent model for electrical properties of multiphase media","authors":"Yigaofei Zhang, Bowen Chen, Xiaodong Yang, Xiaoping Wu","doi":"10.1063/5.0232605","DOIUrl":"https://doi.org/10.1063/5.0232605","url":null,"abstract":"Determining the effective electrical properties of a multiphase medium is essential for understanding its performance. However, accurately characterizing the internal structure and calculating the effective electrical properties of complex multiphase media can be challenging, often resulting in divergent results from different models. In this study, we propose a connectivity dependent model for mixed media based on the effective medium approximation, which incorporates structural influences. This model simplifies itself to analytical forms in specific scenarios, such as simple series and parallel configurations. Our model demonstrates two key advantages: First, the model parameters depend solely on the shape distribution of each phase within the medium, making it applicable to multiphase systems (≥3) without requiring additional corrections. Second, it can predict the percolation threshold and provide insights into permeability and connectivity analyses of the medium. We demonstrate the effectiveness and versatility of our model through a series of parameter analyses and comparisons with experimental data.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"8 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adam Anglart, Agnès Maurel, Philippe Petitjeans, Vincent Pagneux
We present a comprehensive investigation, combining numerical simulations and experimental measurements, into the manipulation of water waves and resonance characteristics within closed cavities utilizing anisotropic metamaterials. We engineer the anisotropic media with subwavelength-scale layered bathymetry through the application of coordinate transformation theory and the homogenization technique to a fully three-dimensional linear water wave problem. Experimental and numerical analyses of deformed cavities employing anisotropic metamaterial bathymetry demonstrate regular sloshing mode patterns and eigenfrequencies akin to those observed in rectangular reference cavities with flat bathymetry. Our study underscores the potential of water wave metamaterials for establishing robust anisotropic metabathymetry for the precise control of sloshing modes.
{"title":"Regular sloshing modes in irregular cavities using metabathymetry","authors":"Adam Anglart, Agnès Maurel, Philippe Petitjeans, Vincent Pagneux","doi":"10.1063/5.0223974","DOIUrl":"https://doi.org/10.1063/5.0223974","url":null,"abstract":"We present a comprehensive investigation, combining numerical simulations and experimental measurements, into the manipulation of water waves and resonance characteristics within closed cavities utilizing anisotropic metamaterials. We engineer the anisotropic media with subwavelength-scale layered bathymetry through the application of coordinate transformation theory and the homogenization technique to a fully three-dimensional linear water wave problem. Experimental and numerical analyses of deformed cavities employing anisotropic metamaterial bathymetry demonstrate regular sloshing mode patterns and eigenfrequencies akin to those observed in rectangular reference cavities with flat bathymetry. Our study underscores the potential of water wave metamaterials for establishing robust anisotropic metabathymetry for the precise control of sloshing modes.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"17 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, with the popularization of the concept of exercise, the determination of fatigue state during exercise in order to achieve the purpose of scientific exercise has become an important research topic. The concentration of urea in urine fluctuates with the change in exercise intensity, so it is widely used as a biochemical indicator for judging sports fatigue. In this paper, a method combining Raman spectroscopy and convolutional neural network is proposed for quantitative analysis of urea in urine. Averaged spectra are combined with the baseline correction of Raman spectra, an approach that significantly improves the quality of the data and further enhances the prediction accuracy of the model. Finally, in the actual quantitative analysis of urine urea, it demonstrated not only high efficiency and simplicity but also very high stability compared with the traditional optical colorimetric method. Thus, it provides a basis for the rapid and accurate assessment of muscle fatigue.
{"title":"Convolutional neural network model-based prediction of human muscle activity by analyzing urine in body fluid using Raman spectroscopy","authors":"Shusheng Liu, Wei Su, Zhenfeng Wang, Qihang Wan, Yinlong Luo, Xiaobin Xu, Liting Chen, Jian Wu","doi":"10.1063/5.0237313","DOIUrl":"https://doi.org/10.1063/5.0237313","url":null,"abstract":"In recent years, with the popularization of the concept of exercise, the determination of fatigue state during exercise in order to achieve the purpose of scientific exercise has become an important research topic. The concentration of urea in urine fluctuates with the change in exercise intensity, so it is widely used as a biochemical indicator for judging sports fatigue. In this paper, a method combining Raman spectroscopy and convolutional neural network is proposed for quantitative analysis of urea in urine. Averaged spectra are combined with the baseline correction of Raman spectra, an approach that significantly improves the quality of the data and further enhances the prediction accuracy of the model. Finally, in the actual quantitative analysis of urine urea, it demonstrated not only high efficiency and simplicity but also very high stability compared with the traditional optical colorimetric method. Thus, it provides a basis for the rapid and accurate assessment of muscle fatigue.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isaiah Gray, Qinwen Deng, Qi Tian, Michael Chilcote, J. Steven Dodge, Matthew Brahlek, Liang Wu
α -MnTe is an antiferromagnetic semiconductor with above room temperature TN = 310 K, which is promising for spintronic applications. Recently, it was reported to be an altermagnet, containing bands with momentum-dependent spin splitting; time-resolved experimental probes of MnTe are, therefore, important both for understanding novel magnetic properties and potential device applications. We investigate ultrafast spin dynamics in epitaxial MnTe(001)/InP(111) thin films using pump-probe magneto-optical measurements in the Kerr configuration. At room temperature, we observe an oscillation mode at 55 GHz that does not appear at zero magnetic field. Combining field and polarization dependence, we identify this mode as a magnon, likely originating from inverse stimulated Raman scattering. Magnetic field-dependent oscillations persist up to at least 335 K, which could reflect coupling to known short-range magnetic order in MnTe above TN. Additionally, we observe two optical phonons at 3.6 and 4.2 THz, which broaden and redshift with increasing temperature.
{"title":"Time-resolved magneto-optical effects in the altermagnet candidate MnTe","authors":"Isaiah Gray, Qinwen Deng, Qi Tian, Michael Chilcote, J. Steven Dodge, Matthew Brahlek, Liang Wu","doi":"10.1063/5.0244878","DOIUrl":"https://doi.org/10.1063/5.0244878","url":null,"abstract":"α -MnTe is an antiferromagnetic semiconductor with above room temperature TN = 310 K, which is promising for spintronic applications. Recently, it was reported to be an altermagnet, containing bands with momentum-dependent spin splitting; time-resolved experimental probes of MnTe are, therefore, important both for understanding novel magnetic properties and potential device applications. We investigate ultrafast spin dynamics in epitaxial MnTe(001)/InP(111) thin films using pump-probe magneto-optical measurements in the Kerr configuration. At room temperature, we observe an oscillation mode at 55 GHz that does not appear at zero magnetic field. Combining field and polarization dependence, we identify this mode as a magnon, likely originating from inverse stimulated Raman scattering. Magnetic field-dependent oscillations persist up to at least 335 K, which could reflect coupling to known short-range magnetic order in MnTe above TN. Additionally, we observe two optical phonons at 3.6 and 4.2 THz, which broaden and redshift with increasing temperature.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"191 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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